Trimmer adjusters for sewing machines



Sept. 16, 1947. N. KNAUs TRIMMER ADJUSTERS FOR SEWING MACHINES Filed oet. 2,1945 2 sheets-sneer 1 S/ttowm v, 9d i, w 4 I r W Sept. 16,1947. N. KNAUs A'.'LRIMMER ADJSTERS FOR SEWING MACHINES 2 Sheets-Sheet 2 Filed Oct. 2, 1945 Patented Sept. 16, 1,947

TRIRIMER ADJUSTERS FOR SEWIN MACHINES Nicholaus Knaus, Cranford, N. J., assignor to The Singer Manufacturing Company, Elizabeth,

N. J., a corporation of New Jersey Application October 2, 1945, Serial No. .619,801

8 Claims.

This invention relates to sewing machines and more particularly to trimming mechanisms therefor of that type adapted to trim off the marginal portion of the work adjacent to and parallel with the line of seam formation.

An overedge sewing machine is a good example Of one form of sewing machine which frequently embodies this type of trimming mechanism; the trimming of the work being effected in advance ot the stitch-forming mechanism and the overedge seam thereafter being formed over the trimmed edge. This invention will, therefore, be shown and. described in connection with an overedg sewing machine, but it is to be understood that its application is in nowise limited to that type of machine.

In overedge sewing machines, the trimming of the work is usually eifected as close to the line of needle penetration as is practical so that the overedge seam may be relatively narrow. It has been found, however, that under certain conditions, such for example as when sewing over cross-seams, inserted elastics, etc., the normal setting of the trimming mechanism relative to the line of needle penetration affords an insufcient amount of material to produce a strong seam. Various mechanisms heretofore have been provided for enabling the operator temporarily to widen the margin between the line of needle penetrations and the trimmed edge of the work, as the nature of the work may require. These prior constructions, however, have been cumbersome and inconvenient to operate and have usually necessitated the lateral shifting of the entire trimming mechanism and portions of its actuating means.

This invention has as its primary object to provide a trimming mechanism of the type comprising relatively movable upper and lower trimmer blades, spring pressed together, and to combine therewith improved means adapted to be actuated by the operator and during the operation of the machine, for shifting the upper trimmer blade laterally of the line of seam formation and relatively to its supporting and actuating means, so that the margin between the line of needle penetration and the edge of the work may be varied at will.

Still another object of the invention is to provide an improved adjusting means for the trimmer shifting mechanism whereby a unit movement of the shifting lever may be caused to give to the upper trimmer blade any pre-selected one of a plurality of predetermined lateral morements.

With the above and other objects in View, as will hereinafter appear, the invention comprises the devices, combinations and arrangements of parts hereinafter set forth and illustrated in the accompanying drawings of a preferred embodiment of the invention, from which the several features of the invention and the advantages attained thereby will be readily understood by those skilled in the art.

In the drawings,

Fig. 1 is a plan view, partly in section, of a portion of an overedge sewing machine embodying the present invention.

Fig. 2 is a vertical sectional view taken substantially on the line 2-2 of Fig. 1.

Fig. 3 is a detail sectional view taken on the line 3-3 of Fig. 2.

Fig. 4 is a detail plan view illustrating one eX- treme adjustment of the arm which carries the trimmer-shifting cam, later to be described.

Fig. 5 is a View similar to Fig. 4 but showing the arm in its other extreme position of adjustment.

Figs. 6 and l are enlarged detail rear end views, partly in section, of the parts shown in Figs. 4 and 5 and with the parts in the same relative positions, respectively.

Referring more specifically to the drawings, the invention is disclosed as embodied in an overedge sewing machine of the type disclosed in United States Patent No. 2,238,796, April 15, 1941, N. Knaus, and in connection with the trimming mechanism similar to that which forms the subject of United States Patent No. 2,293,607, August 18, 1942, Knaus et al.

The machine has a main frame l which supports overedge stitch-forming mechanism comprising a reciprocating curved needle 2, an under or needle-loop-taking looper 3 and an overedge looper 4 which cooperates with the needle and looper 3 in the formation of overedge stitches. The machine also includes a conventional work-feeding mechanism (not shown) and a cooperating presser device (the universal pivot of which is designated as p in Fig. 3) for advancing the work t0 and beyond the stitchforming mechanism, and a trimming mechanism which is adapted to trim the work at one side 0f the line of seam formation. The trimming mechanism comprises an upper vibratory trimmer-bar 5, pivotally mounted, at its rear end 5a on a stud 6 which is supported by the machine frame and is held therein by a set screw 1. Vibratory motions are given to the trimmer-bar by an eccentric `8 secured upon a rotary main shaft 9,

through the medium of a link I having a portion surrounding the eccentric and being pivotally connected at II, to a depending part b of the trimmer-bar 5. The link I0 also has a portion which extends upwardly above the pivotal connection II and serves as a take-up for the needle-thread but as this take-up forms no part of the present invention the upperpart of the link has been broken oii better to disclose features of this invention.

The forward end of the trimmer-bar is formed as a. yoke I2 having spaced arms I2a and-lI-Zb provided with aligned apertures within which is slidingly mounted an endwisemovable rod I3. A trimmer-blade-carrying head -I4 has arms Illa and I4b surrounding the rod I3 and a portion I4 secured to the head I4 and slidable therewith. The head I4 is secured to the rod I3 by means of a set-screw I5 threaded through the arm Illa and bearing upon the rod.. An upper trimmerblade I6 is adjustably secured in a groove I 4d formed in the front face of the portion I4by a clamp-block I'I pressed against the blade by a clamp-screw I8 threaded into the head I 4.

From the foregoing it will be understood that the upper trimmer-blade is carried by the head I4 which is secured to and slidable horizontally in the yoke I2with the rod I3.

The head I4 and the blade I6 carried thereby are normally maintained in one extreme lateral position, i. e., to the leftas viewed in Fig,y l, with the arm IfL in contact with the arm I 2a ofthe yoke. This is effected by an expansion spring I9 inserted within an axial bore formed in the rod I3 and bearing,at one end, against the bottom of the bore and at its opposite end against a pin threaded into the yoke I2 and passing through slots in the rod I3.

Cooperating with the upper movable trimmerblade I6 is a lower normally stationary trimmerblade 2I mountedior endwise adjustment, in a slot v22 formed in a blade-holder 23 and held therein by the head 24a of a clamp-screw 24. The blade-holder 23 is formed integrally with a cylindrical shank v supported, for vlongitudinal movement, in a pedestal Ia forming a part of the main frame of the machine. The screw24 extends through a bore in the shank 25 of the blade-holder and has threaded, on its outer end, a clamp nutv 25 whichbears against a Washer 2Bal which, in turn, abuts the end of the shank 25. Thus by turning the nutY 26 in one direction the screw 24 is moved axially in the bore in the shank 25 thereby causing thehead 24a, ywhich overlies the blade 2I, to clamp the blade .against its holder 23.

The blade-holder 23;.and'the lower trimmer blade 2l .carried thereby, are normally biased toward the right as seen in Fig. 1,V to cause the lower trimmer blade to bear laterally against the upper trimmer blade in all theadjusted positions of thelatter.` This iseiected by a coil. spring 21 fitted within a bore 28 in theshank 25 .and bearing at its inner end against the end wall of the bore and at its outer `end against a fixed `abutment plate 29 secured to the pedestal Ia by a screw 33. The blade-holder is guided Vin its lateral movements by its sliding connection with a stud 3| which is clamped to the pedestal Ia by a screw 32.

As hereinbefore stated, this invention relates primarily to means for shifting the trimmerblades laterally of the line of vseamiormation during the operation of the'machine. This is effected by mechanism now tobe described.

spring I 9.

f Adjacent its rear end, the member 33 is formed Y -asa loopV 33h through which freely passes the hub 5a of the trimmer-bar 5 (Fig. 3). The member-33 projectsrearwardly beyond the loop 33b and terminates in a rear end portion 33 which is engaged by a manually actuated cam 36, later to be described, which turns the member about its pivot 34 to effect lateral adjustment of the upper-trimmer blade. If desired, the rear end of the member 33 may carry a roller 31 for engagement ,by vthecam 36, but such roller. isY not essential.. As' shown herein, theroller is-proyided but it Vmay be consideredyto `be a -part `offthe member 33.

Pivotally mounted on the stud Grand straddling that :portion of the main frame I-in-vvhich` the studA is mounted (Fig. 3) arethe `downturned and laterallyy spaced portions 38'1of a manually actuable lever. 38. -fOne portionofI the leverextends forwardly from. its pivotover` the machine to the front thereof where. itis formed with a finger, piece 39 conveniently accessibleto the hand of the operator when in her-normal Working: position. The-'lever 238 also has arearw-ardly extending arm '40 adapted -to be connected, as.; by a chain 4I, to either a kneeforffoot actuated treadle not shown.

. As used herein, in-reference to Vvthe lever `38, the term manually actuated isY intended to mean a lever actuated by any party ofthe person of the operator.

A torsion spring '42 surrounding thespiojecting end Iia of the stud 5 Aand havingone1lirnb'42a engaging: the arm l0-and itsf other limbf42banchored inthe main frame I (Fig. 1) normally holds the4 lever: 38- in the position ,illustrated in full Alines in Fig. 2 with the'forward-end portion resting on the machine frame.

Pivotally mounted. on the fupper face of the lever-3, by aY shoulder screw 43, is-an arm` 44 having a downturned portion l which overhangs the lever. and carries the` trimmer-shifting cam 36, h'ereinbefore mentioned. ',Thus turning of the lever 38, by hand,.foot or otherwise,

from the position shown in full'linesin Fig. 2 to the position indicated in dottedlineswcausesfthe cam 33 to be brought into contactwith the rear end of the memberV 33 and to swing thatmember about its pivot.34;counterclockwise as viewed in Fig. l. This movement ofthe member 33 shifts the uppertrimmer-bladeaway from the line of needle penetration in opposition to the spring I3, thereby increasing the margin between the line of needle penetrationand the trimmed edge of the work. As vabovev stated, the lower trimmer blade is shiftable laterally bythe springZ'I land bears against the upper trimmer blade in .allthe adjusted positions thereof. A stop plate 46, supported by a guard member 41 secured tothe 4main frame, forms an abutment -or the lever 38, as indicated in dotted lines'in Fig. 2, thereby-predetermining the unit angularrnovement which may be given to the lever.

The extent of movement given to the member 33, and thereby to the upper trimmer-bladefby a unit movement ofthe lever 38 is dependent upon the setting of the cam 36 relative to the rear end of the member 33, herein shown as comprising the roller 31. To enable the arm 44, and the cam carried thereby, to be set at various distances from the roller 31 and locked in their adjusted positions, the arm is provided with a series of apertures a arranged in a row extending lengthwise of th'e arm. Upon swinging of the arm on its pivot 43, the apertures a are successively aligned with complemental apertures b formed in the lever 34 and arranged in a row extending obliquely of the length of the lever and intersecting the row of apertures a. A threaded stud 48, having a knurled head 49, is adapted to be passed through the apertures a and threaded into an aligned aperture therebeneath, thereby to lock the arm 44 to the lever 38 in various positions of adjustment of the arm.

In Figs. 1, 4 and 6 the stud 48 is shown as inserted into the rearmost ones of the apertures a and b. In this setting of the parts the cam 36, carried by the arm 44, Wholly overlies the roller 31 and therefore a unit movement of the lever 38 will cause the cam to shift the roller, and the rear end of the member 33 which carries it, from the position shown in full lines in Figs. l and 6 to the position indicated in dotted lines. This causes the forward end of the member 33 to give to the trimmer-blade carrier I4, and the upper trimmer-blade I6 carried thereby, their maximum movements to the right as viewed in Fig. l.

In Figs. 5 and 7, the arm 44 is shown as swung horizontally about its pivot 43 to position the foremost apertures a and b in line for the reception of the stud 48 to effect minimum lateral adjustment of the upper trimmer blade. As shown most clearly in Fig. 1, this setting of the parts places a portion of the cam 36 to one side of a vertical plane tangential to the roller 31, whereupon a unit movement of the lever 38, arm 44 and cam 36 will have a less shifting eil'ect upon the roller 31 as compared with the setting shown in Fig. 6, as indicated by the full and dotted line positions in Fig. 7, thus giving to the upper trimmer blade carrier a substantially less lateral movement. Insertion of the stud 48 into the intermediate apertures a and b will cause the upper trimmer blade carrier to be given intermediate lateral adjustments by a unit movement of the lever 38. By having the apertures a and b arranged in intersecting rows at an acute angle to each other it is possible to obtain very ne increments of adjustment together with a positive locking of the parts.

Having thus set forth the nature of the invention, what I claim herein is:

l. In a sewing machine, in combination, a frame, a trimmer-bar mounted on said frame, means to actuate said trimmer-bar, an upper trimmer-blade adjustably carried by said trimmer-bar, a cooperating lower trimmer-blade carried by said frame, means for maintaining said trimmer-blades in working contact with each other, and means for shifting said upper trimmerblade laterally on said trimmer-bar comprising a trimmer-shifting member pivotally mounted intermediate its ends on said trimmer-bar and operatively connected at its forward end with said upper trimmer-blade, a manually actuable lever fulcrumed on said frame and adapted to be given a unit movement, a trimmer-shifting cam supported by said lever and adapted upon movement of the lever to engage the rearward end of said member thereby to shift the member and the uppertrimmer Ablade," and-means to adjust said cam on said lever to -vary the amplitude of movement given to said member and upper trimmer-blade by the unitmovement of said lever.

2. A sewing machineas' set forth in claim 1 in which the trimmer-shifting cam is carried by an arm adjustably mounted on the manually actuable lever and adjustable toward and from th'e rearward end of the pivoted trimmer-shifting.

member, and 'in which means is provided for securing said arm to said lever in any one of a pluralityof positions to vary the effectiveness of the cam on said member. g v

3. A sewing machine as set forth in claim l in which the trimmer-shifting cam is carried by an arm pivotally mounted `on the manually actuable lever and adjustable toward and from the rearward end of the pivoted trimmer-shifting member, and in which' means is provided for securing said arm to said lever in any one of a plurality of predetermined angular positions.

4. A sewing machine as set forth in claim 1 in which the trimmer-shifting cam is carried by an arm adjustably mounted on the manually actuable lever and adjustable toward and from the rearward end of the pivoted trimmer-shifting member, and in which a locking stud passing through said arm and entering any one of a series of apertures in the lever, locks the two together in various positions of adjustment thereby to vary the effectiveness of the cam on said member.

5. A sewing machine as set forth in claim 1 in which the trimmer-shifting cam is carried by one end of an arm pivotally mounted at its opposite end on the manually actuable lever and swingable toward and from the rearward end of the trimmer-shifting member; in which the arm and lever are each provided with a series of apertures adapted to be successively aligned by the swinging movement of the arm; and in which a stud is adapted to be inserted into the aligned apertures to lock the arm to the lever in the various positions of adjustment of the arm.

6. A sewing machine as set forth in claim l in which th'e trimmer-shifting cam is carried by one end of an arm pivotally mounted at its opposite end on the manually actuable lever and swingable toward and from the rearward end of the trimmer-shifting member; in which the arm and lever are provided with intersecting rows of apertures, the individual apertures of said rows being adapted to be successively aligned by the swinging movement of the' arm; and in which a stud is adapted to be inserted into the aligned apertures to lock the arm to the lever in various positions of the arm.

7. A sewing machine as set forth in claim 1 in which the manually actuable lever is located above the level of the trimmer shifting member and pivotally supports an arm having a downwardly extending portion which overhangs the edge of the lever and carries the trimmer-shifting cam; in which the lever is provided with a row of apertures arranged at an acute angle to the longitudinal axis of the lever; in which the arm is provided with a row of apertures arranged in line with the longitudinal axis of the arm and adapted to be aligned successively with the apertures in the lever by angular movement of th'e arm; and in which a stud is adapted to be inserted into the aligned apertures to lock the arm to the lever with the cam in various operative positions relative to the trimmer-shifting member.

8. VA trimming mechanism for sewing machines comprising a horizontally disposed trimmer-bar, means to actuate said trimmerfbar, a, trimmerblade carrying head adjustably mounted on said trimmeribar, an upper trimmer-blade mounted on s aid head, a, cooperating lower trimmer-blade, means for `maintaizving said trimmer blades in working. Contact with each other, a member pivota'lly supported by said trimmer-bar, an operative cpnnection betweenone end of said member andsaidhead, a manually shiftable lever, a cam carried by saidlever and acting on the other end of said member to shift the member 'and thereby said upper trimmer-blade, and means for adjusting the-position of `said cam on said lever, thereby toi/ary the actionof thepcam on said member by a unit movement of said lever. Y l

' NICHOLAUS KNAUS.

8 REFERENCES CITED The following.referentiesl arelof'record in the file of this patent:

UNITED STATESy PATENTS' Number Name Datef 2,293,607 Knaus et a1. Aug. 18,1942

1,302,024 Evensen Apr. 29, 1919 868,086 Hanson et al. Oct. 15, 1907 FOREIGN PATENTS Number Country Date v 543,235 Great Britain Feb. 16, 1942 

